1. Field of the Invention
The present invention relates to a developer cartridge and an image forming apparatus to which the developer cartridge is attached.
2. Description of the Related Art
A conventional image-forming apparatus such as an electrophotographic printer, a copying machine, and a facsimile machine performs an electrophotographic process. A charging roller charges the surface of a photoconductive drum uniformly. An exposing unit illuminates the charged surface of the photoconductive drum to form an electrostatic latent image on the photoconductive drum. A developing roller applies toner to the electrostatic latent image to develop it into a toner image. Then, a transfer roller transfers the toner image onto printing paper. The printing paper is then advanced to a fixing unit where the toner image is fixed into a permanent image.
FIG. 15 is a schematic view of a conventional image-forming apparatus. An image-forming apparatus 26 includes yellow, magenta, cyan, and black image-forming sections 44Y, 44M, 44C, and 44BK. The image-forming sections incorporate photoconductive drums 27Y, 27M, 27C, and 27BK and transfer rollers 34Y, 34M, 34C, 34BK. The photoconductive drums 27Y, 27M, 27C and 27BK oppose corresponding transfer rollers 34Y, 34M, 34C, and 34BK with a transfer belt 33 sandwiched therebetween. A belt-cleaning section 35 is located under the transfer belt 33 and removes toner adhering to the transfer belt 33. The transfer belt 33, transfer rollers 34Y, 34M, 34C, and 34BK, and belt-cleaning section 35 form a transfer section 45.
The image-forming sections 44Y, 44M, 44C, and 44BK will be described. Each of the image-forming sections 44Y, 44M, 44C, and 44BK may be substantially identical; for simplicity only the operation of the image forming section 44BK for forming black images will be described, it being understood that the other image forming sections may work in a similar fashion.
Disposed around the photoconductive drum 27 are a cleaning unit 28, neutralizing lamp 29, a charging roller 30, an exposing unit 31, and a developing roller 32, which are aligned in this order from upstream to downstream with respect to the rotation of the photoconductive drum 27. A transporting mechanism 41 is disposed immediately below the cleaning unit 28 and transports the toner removed by the cleaning unit 28 from the photoconductive drum 27.
A toner discharging path 17 runs along the transfer belt 33 under the image-forming sections 44Y, 44M, 44C, and 44BK. The transporting mechanism 41 transports the waste toner to the toner discharging path 17, so that the waste toner is finally collected into a waste toner reservoir 11.
The operation of the image-forming apparatus 26 of the aforementioned configuration will be described. Paper 40 is advanced from a paper tray 36 into a paper path through which the paper 40 is fed by the transport roller 37 into a gap between the photoconductive drum 27 and the transfer belt 33.
The neutralizing lamp 29 neutralizes residual charges on the surface of the photoconductive drum 27BK of the image-forming section 44BK. The charging roller 30BK uniformly charges the entire cylindrical surfaces of the photoconductive drum 27BK. The exposing unit 31 irradiates the charged surface of the photoconductive drum 27BK with light to form an electrostatic latent image. Then, the developing roller applies toner to the electrostatic latent image to develop the electrostatic latent image into a toner image. The toner image is then transferred onto the paper 40, and then fixed into a permanent image in the fixing unit 38. Then, the paper 40 having a permanent image thereon is ejected onto a stacker 39.
Some of the toner fails to be transferred onto the paper 40 and is left on the photoconductive drum 27BK. The residual toner is removed as waste toner and the waste toner is transported by the transporting mechanism 41. The toner may also adhere to the transfer belt 33 due to poor charging and may be transferred onto the transfer belt during an image-density correcting operation. The toner on the transfer belt is removed by the belt-cleaning section 35 and collected into the waste toner reservoir 11.
The waste toner reservoir 11 will be described. FIG. 16 is a cross-sectional view of a conventional waste toner reservoir 11. FIG. 17 is a cross-sectional view of another conventional waste toner reservoir.
Referring to FIG. 15, a box-like waste toner reservoir 11 is formed with an opening 42 through which the aforementioned toner discharging path 17 extends into the waste toner reservoir 11. The waste toner is removed from the photoconductive drum 27 by the cleaning unit 28 and transported by the transporting mechanism 41 to the toner discharging path 17. A simple sealing member 43 is disposed for providing a sealed environment for the waste toner reservoir 11. The sealing member 43 holds the toner discharging path 17 fitted into the opening 42, thereby improving sealing effect to prevent toner particles from scattering. The opening 42 may be formed in a top portion or a side portion of the waste toner reservoir 11.
With the aforementioned conventional image-forming apparatus 26, if the waste toner reservoir is tilted or subjected to impact during replacement of the waste toner reservoir 11, the toner may fall through the opening 42 impairing the ability of the waste toner reservoir to handle the waste toner.